Sökning: "NATURAL SCIENCES Chemistry Theoretical chemistry Quantum chemistry"

Visar resultat 21 - 25 av 189 avhandlingar innehållade orden NATURAL SCIENCES Chemistry Theoretical chemistry Quantum chemistry.

1. 21. Matrix Algebra for Quantum Chemistry

   Författare :Emanuel H. Rubensson; Pawel Salek; Stefan Goedecker; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; linear scaling; reduced complexity; electronic structure; density functional theory; Hartree-Fock; density matrix purification; congruence transformation; inverse factorization; eigenvalues; eigenvectors; numerical linear algebra; occupied subspace; canonical angles; invariant subspace; Theoretical chemistry; Teoretisk kemi;

   Sammanfattning : This thesis concerns methods of reduced complexity for electronic structure calculations.  When quantum chemistry methods are applied to large systems, it is important to optimally use computer resources and only store data and perform operations that contribute to the overall accuracy. LÄS MER

3. 22. For a Fistful of Qubits: Computational Quantum Chemistry on Near-Term Quantum Computers

   Författare :Mårten Skogh; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nonadiabatic processes; quantum error mitigation; variational quantum algorithms; quantum computation; computational chemistry;

   Sammanfattning : Quantum computing has been touted as a great new frontier of computation, pushing the limits of what we consider within reach of computation. While not all problems are expected to be efficiently solved by a quantum computer, quantum chemistry is among those where many have speculated on near-term quantum advantage. LÄS MER

4. 23. Modelling Chemical Reactions : Theoretical Investigations of Organic Rearrangement Reactions

   Författare :Per-Erik Larsson; Sten Lunell; Nessima Salhi-Benachenhou; Olle Matsson; Osvaldo Goscinski; Ian H. Williams; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; Kvantkemi; Quantum chemistry; Kvantkemi; Quantum Chemistry; Kvantkemi;

   Sammanfattning : Chemical reactions are ubiquitous and very important for life and many other processes taking place on earth. In both theoretical and experimental studies of reactivity a transition state is often used to rationalise the outcome of such studies. LÄS MER

5. 24. Theoretical Reflections of Solvation in Polar Media

   Författare :Daniel Hagberg; Beräkningskemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kvantkemi; Teoretisk kemi; quantum chemistry; Theoretical chemistry; Coordination; Water; Uranyl; Intermolecular forces; Simulation; Dielectric; Cluster; Hofmeister series; Ion; Interaction; Dipole;

   Sammanfattning : Using experiments it is rather easy to measure things on the macroscopic length scale, while it is much harder to measure something in the microscopic world like molecular structure. The opposite is true in theoretical chemistry. LÄS MER

7. 25. Quantum Chemical Exploration of Nitriles in Prebiotic Chemistry and Astrobiology

   Författare :Hilda Sandström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; metadynamics; astrochemistry; iminoacetonitrile; hydrogen cyanide; acrylonitrile; azotosome; Titan;

   Sammanfattning : The Universe hosts countless different chemical environments, such as planets, moons, comets and the interstellar medium. The diverse pressures, temperatures and chemical compositions of these environments make a wide variety of processes possible. LÄS MER